chrome/common/extensions/docs/server2/local_git_util.py

   1 # Copyright 2015 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import os
   6 import re
   7
   8 from file_system import FileNotFoundError
   9
  10
  11 # This provides utilities for extracting information from the local git
  12 # repository to which it belongs.
  13
  14
  15 # Regex to match ls-tree output.
  16 _LS_TREE_REGEX = re.compile(
  17     '\d+\s(?P<type>\w+)\s(?P<id>[0-9a-f]{40})\s(?P<name>.*)')
  18
  19
  20 def _GetRoot():
  21   return os.path.join(os.path.dirname(os.path.realpath(__file__)),
  22                       os.pardir, os.pardir, os.pardir, os.pardir, os.pardir)
  23
  24
  25 def _RelativePath(path):
  26   return os.path.join(_GetRoot(), path)
  27
  28
  29 def RunGit(command, args=[]):
  30   # We import subprocess symbols lazily because they aren't available on
  31   # AppEngine, and the frontend may load (but should never execute) this module.
  32   from subprocess import check_output
  33   with open(os.devnull, 'w') as dev_null:
  34     return check_output(['git', command] + args, stderr=dev_null,
  35         cwd=_GetRoot())
  36
  37
  38 def ParseRevision(name):
  39   return RunGit('rev-parse', [name]).rstrip()
  40
  41
  42 def GetParentRevision(revision):
  43   return RunGit('show', ['-s', '--format=%P', revision]).rstrip()
  44
  45
  46 def GetRootTree(revision):
  47   return RunGit('show', ['-s', '--format=%T', revision]).rstrip()
  48
  49
  50 def ListDir(path, revision='HEAD'):
  51   '''Retrieves a directory listing for the specified path and optional revision
  52   (default is HEAD.) Returns a list of objects with the following properties:
  53
  54     |type|: the type of entry; 'blob' (file) or 'tree' (directory)
  55     |id|: the hash of the directory entry. This is either tree hash or blob hash
  56     |name|: the name of the directory entry.
  57   '''
  58   from subprocess import CalledProcessError
  59   try:
  60     ref = '%s:%s' % (ParseRevision(revision), path.lstrip('/'))
  61     listing = RunGit('ls-tree', [ref]).rstrip().splitlines()
  62   except CalledProcessError:
  63     raise FileNotFoundError('%s not found in revision %s' % (path, revision))
  64
  65   def parse_line(line):
  66     return re.match(_LS_TREE_REGEX, line).groupdict()
  67
  68   return map(parse_line, listing)
  69
  70
  71 def ReadFile(path, revision='HEAD'):
  72   '''Retrieves the contents of a file at the specified path and optional
  73   revision (default is HEAD.) Returns its contents as a string.
  74   '''
  75   from subprocess import CalledProcessError
  76   try:
  77     return RunGit('show', ['%s:%s' % (ParseRevision(revision), path)])
  78   except CalledProcessError:
  79     raise FileNotFoundError('%s not found in revision %s' % (path, revision))